US6412469B1 — Fuel injection control system for diesel engine

Claim 1

Independent Claim 205 words

A method of controlling a fuel injection of a multi-cylinder diesel engine, said method comprising: deciding whether a pilot fuel injection is executed; deciding whether an operating condition of the engine is in a predetermined low-load operating region; calculating a mono-cylinder fuel injection quantity for each cylinder of the engine when the engine operating condition is in the predetermined low-load operating region; calculating a common fuel injection quantity common among the cylinders of the engine when the engine operating condition is out of the predetermined low-load operating region; calculating a mono-cylinder pilot fuel injection quantity for each cylinder by multiplying a predetermined ratio to the fuel injection quantity when the engine operating condition is in the predetermined low-load operating region and when the pilot fuel injection is executed; calculating a common pilot fuel injection quantity common among the cylinders when the engine operating condition is out of the predetermined low-load operating region and when the pilot fuel injection is executed; and calculating a main fuel injection quantity by one of a first method of subtracting the mono-cylinder pilot fuel injection quantity from the mono-cylinder fuel injection quantity and a second method of subtracting the common pilot fuel injection quantity from the common fuel injection quantity.

Claim 2

Independent Claim 205 words

A method of controlling a fuel injection of a multi-cylinder diesel engine, said method comprising: deciding whether a pilot fuel injection is executed; deciding whether an operating condition of the engine is in a predetermined low-load operating region; calculating a mono-cylinder fuel injection quantity for each cylinder of the engine when the engine operating condition is in the predetermined low-load operating region; calculating a common fuel injection quantity common among the cylinders of the engine when the engine operating condition is out of the predetermined low-load operating region; calculating a mono-cylinder pilot fuel injection quantity for each cylinder by multiplying a predetermined ratio to the fuel injection quantity when the engine operating condition is in the predetermined low-load operating region and when the pilot fuel injection is executed; calculating a common pilot fuel injection quantity common among the cylinders when the engine operating condition is out of the predetermined low-load operating region and when the pilot fuel injection is executed; and calculating a main fuel injection quantity by one of a first method of subtracting the mono-cylinder pilot fuel injection quantity from the mono-cylinder fuel injection quantity and a second method of subtracting the common pilot fuel injection quantity from the common fuel injection quantity.

Claim 3

Dependent Claim 212 words

A fuel injection control system for a multi-cylinder diesel engine, comprising: a control unit arranged to decide whether a pilot fuel injection is executed, to decide whether an operating condition of the engine is in a predetermined low-load operating region, to calculate a mono-cylinder fuel injection quantity for each cylinder of the engine when the engine operating condition is in the predetermined low-load operating region, to calculate a common fuel injection quantity common among the cylinders of the engine when the engine operating condition is out of the predetermined low-load operating region, to calculate a mono-cylinder pilot fuel injection quantity for each cylinder by multiplying a predetermined ratio to the fuel injection quantity when the engine operating condition is in the predetermined low-load operating region and when the pilot fuel injection is executed, to calculate a common pilot fuel injection quantity common among the cylinders when the engine operating condition is out of the predetermined low-load operating region and when the pilot fuel injection is executed, and to calculate a main fuel injection quantity by one of a first method of subtracting the mono-cylinder pilot fuel injection quantity from the mono-cylinder fuel injection quantity and a second method of subtracting the common pilot fuel injection quantity from the common fuel injection quantity.

Claim 4

Dependent Claim 212 words

A fuel injection control system for a multi-cylinder diesel engine, comprising: a control unit arranged to decide whether a pilot fuel injection is executed, to decide whether an operating condition of the engine is in a predetermined low-load operating region, to calculate a mono-cylinder fuel injection quantity for each cylinder of the engine when the engine operating condition is in the predetermined low-load operating region, to calculate a common fuel injection quantity common among the cylinders of the engine when the engine operating condition is out of the predetermined low-load operating region, to calculate a mono-cylinder pilot fuel injection quantity for each cylinder by multiplying a predetermined ratio to the fuel injection quantity when the engine operating condition is in the predetermined low-load operating region and when the pilot fuel injection is executed, to calculate a common pilot fuel injection quantity common among the cylinders when the engine operating condition is out of the predetermined low-load operating region and when the pilot fuel injection is executed, and to calculate a main fuel injection quantity by one of a first method of subtracting the mono-cylinder pilot fuel injection quantity from the mono-cylinder fuel injection quantity and a second method of subtracting the common pilot fuel injection quantity from the common fuel injection quantity.

Claim 5

Dependent Claim 47 words

The fuel injection control system as claimed in claim 2 , wherein said control unit is arranged to calculate the fuel injection quantity for each cylinder by adding a basic fuel injection quantity commonly employed to the cylinders to a correction fuel injection quantity for each cylinder.

Claim 6

Dependent Claim 79 words

The fuel injection control system as claimed in claim 2 , wherein said control unit is arranged to obtain the parameter indicative of the engine operating condition, to calculate a decision value indicative of degree of a demand for executing the pilot fuel injection on the basis of the parameter, and to decide that the pilot fuel injection is executed when the degree of the demand for executing the pilot fuel injection is greater than a first slice level.

Claim 7

Dependent Claim 66 words

The fuel injection control system as claimed in claim 4 , wherein said control unit is arranged to obtain a plurality of parameters indicative of the engine operating condition, to calculate a basic value as to the decision value for each cylinder by using evaluation functions for the respective parameters, and to select a largest one of the plurality of basic values as the decision value.

Claim 8

Dependent Claim 100 words

The fuel injection control system as claimed in claim 4 , wherein said control unit is arranged to obtain a vibration level of the engine, to calculate a feedback correction gain for a feedback control of the pilot fuel injection quantity on the basis of a difference between the decision value and the first slice level, to calculate a feedback correction quantity on the basis of the vibration level, a target vibration level and the feedback correction gain, and to correct the pilot fuel injection quantity by means of the feedback correction quantity when the pilot fuel injection is executed.

Claim 9

Dependent Claim 111 words

The fuel injection control system as claimed in claim 4 , wherein the control unit is arranged to obtain a vibration level of the engine, to calculate a correction allow limiter for a feedback control of the pilot fuel injection quantity on the basis of a difference between the decision value and the first slice level, to calculate the feedback correction quantity on the basis of the vibration level and a target vibration level, to limit the feedback correction quantity within a range of the correction allow limiter, and to correct the pilot fuel injection quantity by means of the limited feedback correction quantity when the pilot fuel injection is executed.

Claim 10

Dependent Claim 128 words

The fuel injection control system as claimed in claim 4 , wherein said control unit is arranged to obtain a vibration level of the engine, to calculate a feedback correction quantity of the pilot fuel injection quantity on the basis of the vibration level and a target vibration level, to calculate a learning correction value of the pilot fuel injection quantity on the basis of the feedback correction quantity when the decision value indicative of the degree of the demand for executing the pilot fuel injection is greater than a second slice level which is greater than the firs slice level, and to correct the pilot fuel injection quantity by means of the feedback correction quantity and the learning correction quantity when the pilot fuel injection is executed.

Claim 11

Dependent Claim 101 words

The fuel injection control system as claimed in claim 4 , wherein said control unit is arranged to obtain two parameters indicative of the engine operating condition, to calculate a basic value of a decision value from one of the two parameter by using an evaluation function with respect to the one parameter, to calculate a correction value of the decision value from the other of the two parameters by using an evaluation function with respect to the other parameter, and to take a value obtained by correcting the basic value by means of the correcting value as the decision value.

Claim 12

Dependent Claim 116 words

The fuel injection control system as claimed in claim 9 , wherein the parameter indicative of the engine operating condition includes an intake air pressure, the evaluation function, which represents a relationship between the degree of the demand for executing the pilot fuel injection and the intake air pressure, being set such that the degree of the demand is low when the intake air pressure is in a low intake air pressure region, that the degree of the demand is high when the intake air pressure is in an intermediate intake air pressure region, and that the degree of the demand is low when the intake air pressure is in a high intake air pressure region.

Claim 13

Dependent Claim 123 words

The fuel injection control system as claimed in claim 9 , wherein the parameter indicative of the engine operating condition includes an intake air flow rate, the evaluation function, which represents a relationship between the degree of the demand for executing the pilot fuel injection and the intake air flow rate, being set such that the degree of the demand is low when the intake air flow rate is in a low intake air flow rate region, that the degree of the demand is high when the intake air flow rate is in an intermediate intake air flow rate region, and that the degree of the demand is low when the intake air flow rate is in a high intake flow rate region.

Claim 14

Dependent Claim 71 words

The fuel injection control system as claimed in claim 9 , wherein the parameter indicative of the engine operating condition includes an excess air ratio, the evaluation function, which represents a relationship between the degree of the demand for executing the pilot fuel injection and the excess air ratio, being set so that the degree of the demand is high when the excess air ratio is in a large ratio region.

Claim 15

Dependent Claim 71 words

The fuel injection control system as claimed in claim 9 , wherein the parameter indicative of the engine operating condition includes a fuel injection quantity, the evaluation function, which represents a relationship between the degree of the demand for executing the pilot fuel injection and the fuel injection quantity, being set so that the degree of the demand is high when the fuel injection quantity is in a small quantity region.

Claim 16

Dependent Claim 80 words

The fuel injection control system as claimed in claim 9 , wherein the parameter indicative of the engine operating condition includes a pressure ratio of an actual fuel injection pressure with respect to a target fuel injection pressure, the evaluation function, which represents a relationship between the degree of the demand for executing the pilot fuel injection and the pressure ratio, being set so that the degree of the demand is high when the pressure ratio is higher than 1.

Claim 17

Dependent Claim 71 words

The fuel injection control system as claimed in claim 9 , wherein the parameter indicative of the engine operating condition includes an integral of an output of an acceleration sensor, the evaluation function, which represents a relationship between the degree of the demand for executing the pilot fuel injection and the integral, being set so that the degree of the demand is high when the integral is in a high region.

Claim 18

Dependent Claim 65 words

The fuel injection control system as claimed in claim 9 , wherein the parameter indicative of the engine operating condition includes a cooling-water temperature, the evaluation function, which represents a relationship between the degree of the demand for executing the pilot fuel injection and the cooling-water temperature, being set so that the degree of the demand increases according to lowering of the cooling water temperature.

Claim 19

Dependent Claim 67 words

The fuel injection control system as claimed in claim 9 , wherein the parameter indicative of the engine operating condition includes an exhaust gas recirculation (EGR) ratio, the evaluation function, which represents a relationship between the degree of the demand for executing the pilot fuel injection and the EGR ratio, being set so that the degree of the demand increases according to decrease of the EGR ratio.

Claim 20

Dependent Claim 110 words

The fuel injection control system as claimed in claim 9 , wherein the parameter indicative of the engine operating condition includes an intake air temperature, the evaluation function, which represents a relationship between the degree of the demand for executing the pilot fuel injection and the intake air temperature, being set so that the degree of the demand is high when the intake air temperature is in a low temperature region, that the degree of the demand is low when the intake air temperature is in an intermediate temperature region, and that the degree of the demand is high when the intake air temperature is in a high temperature region.

Claim 21

Dependent Claim 140 words

The fuel injection control system as claimed in claim 9 , wherein the parameter indicative of the engine operating condition includes at least two of an intake air pressure, an excess air ratio, a fuel injection quantity, a ratio of an actual fuel injection pressure with respect to a target fuel injection pressure, an integral of an output of an acceleration sensor, a cooling-water temperature, an EGR ratio and an intake air temperature, said control unit having the evaluation functions, which represent relationships between the degree of the demand for executing the pilot fuel injection and the parameter, said control unit calculating the degree of the demand for executing the pilot fuel injection from each of the evaluation function and the parameter, said control unit taking a largest one of the calculated degrees of the demand as the decision value.

Claim 22

Dependent Claim 80 words

The fuel injection control system as claimed in claim 19 , wherein the control unit has a plurality of evaluation functions which represent relationships between the degree of the demand for executing the pilot fuel injection and the parameter, said evaluation functions being divided into a basic value calculation function and a correction value calculation function, said control unit correcting a value obtained from the basic value calculating function by means of a value obtained from the correction calculation function.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2005-07-01	2005-12-31	2006-07-02	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2009-07-01	2009-12-31	2010-07-02	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2013-07-01	2013-12-31	2014-07-02	$7700.00	Window Closed / Lapsed

Fuel injection control system for diesel engine

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